1. Field of the Invention
The invention is related to a process for the production of cycloalkane epoxides by the air oxidation of cycloalkenes, and is particularly related to such a process conducted in the presence of a boron-containing catalyst.
2. Description of Relevant Methods
The production of ethylene oxide from ethylene has long been known. However, there has been a less successful search for a similar process for producing other oxides directly from olefins in an economic manner. The same processes which produced ethylene oxide cannot be adapted to the production of other oxides.
As a result, a number of different schemes to produce olefin oxides from olefins or to produce an intermediate to olefin oxides from olefins have been proposed. One segment of the research effort seemed to be directed to producing an olefin oxide directly from the olefin in the presence or absence of a solvent. U.S. Pat. No. 2,649,463 describes the production of a coordination complex created by the reaction of an olefin with a metal halide where the metal is copper, platinum, palladium, iridium, aluminum, zinc, silver, mercury or antimony. This coordination complex is further reacted with oxygen at a high temperature to produce the olefin oxide plus oxygen-containing metal halides. Hawkins, et al. in an article entitled, "Autoxidation of Olefins," in the Journal of Applied Chemistry, Vol. 6, 1956, pgs 1 through 10, describes a process for the production of epoxides directly from olefins and molecular oxygen over magnesium oxide and/or cobalt naphthenate. The direct production of olefin oxides from a mono olefin and a saturated hydrooarbon with oxygen and water, organic acids or olefin oxide in low concentration is described in U.S. Pat. No. 2,780,634.
Brill, et al. in Journal of Organic Chemistry, Vol. 29, 1964, pgs 140-143, describes a process for passing olefins and oxygen, frequently in contact with or dissolved in benzene over various catalysts such as azobisisobutyronitrile, cadmium oxide, cobaltic acetylacetonate, magnesium oxide or methyl ethyl ketone peroxide to produce various oxidation products, including the desired epoxides. U.S. Pat. No. 3,132,156 reveals that ethylene, propylene or butylene oxide may be produced directly from ethane, propane or butane under very precise conditions. These conditions include a temperature of between 425.degree. to 575.degree. C., an oxygen volume percent of between 4 and 14, a contact time with the oxygen of between 0.07-1.5 seconds, a pressure of between 20 to 150 psig and constant concentrations of reactants. Epoxides may also be produced from olefins and oxygen which are in an inert reaction medium when they are brought in contact with a rhenium catalyst and 0.05 to 15 weight percent of a reaction modifier comprised of an alkyl aryl or cyclo alkyl cyanide, pyridine or quinoline in accordance with the invention described in U.S. Pat. No. 3,316,279.
Other schemes for producing olefin oxides from olefins and oxygen by means of a solvent or liquid reaction medium include the following. U.S. Pat. No. 3,153,058 employs polyacyl esters of polyhydroxy alkanes, polyhydroxy cycloalkanes, polyglycols or mixtures thereof as the solvent. Materials selected from saturated aliphatic, alicyclic and aromatic nitriles and mixtures thereof form the solvent in U.S. Pat. No. 3,210,180. Boric acid esters form the liquid reaction medium in U.S. Pat. No. 3,210,381. U.S. Pat. No. 3,228,967 uses major amounts of acetone as the solvent. Carbonic acid esters are employed in U.S. Pat. No. 3,228,968, and at least 25 percent by weight of certain ketones serves as the reaction medium in U.S. Pat. No. 3,232,957. Halogenated benzenes serve as the solvent in U.S. Pat. No. 3,238,229 while benzoic acid esters are employed in a similar reaction described in U.S. Pat. No. 3,281,433. Olefin oxides may be prepared directly from olefins and oxygen over a hydrocarbon soluble, phosphorous molybdenum-hydroxy compound catalyst according to the disclosure in U.S. Pat. No. 3,856,826. The approach of making epoxides directly has never been commercially feasible because all of the methods explored gave low yields of epoxides.
Some of the more recent patents in this field include the following methods to make glycol esters which are precursors to the epoxides. Esters may be produced from olefins in an acid plus oxygen over a tin or cerium catalyst in the presence of iodide as revealed by U.S. Pat. No. 4,154,957. Saturated vicinal esters may be produced from olefins, carboxylic acids and oxygen in the presence of a boron-containing catalyst according to the invention of U.S. Pat. No. 4,220,800. U.S. Pat. No. 4,221,916 teaches that olefins, carboxylic acids and oxygen when reacted together over a vanadium or ruthenium-containing catalyst can also produce saturated vicinal esters. U.S. Pat. No. 4,238,624 discloses a procedure by which ethylene, oxygen and a lower alkanoic acid are reacted together over an iodine source in a bismuth stabilized tellurium oxide catalyst on a carbon support to give ethylene glycol mono-and dialkanoates. U.S. Pat. No. 4,069,381 reveals how glycol monoesters may be made from olefins, oxygen and carboxylic acids over a catalyst system where the cation is zirconium, niobium, molybdenum, hafnium, tantalum, tungsten or rhenium where the anion is a halide in the presence of lithium, sodium, potassium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, aluminum or silver.
Methods also exist for converting the ester intermediates into the epoxides. For example, U.S. Pat. No. 4,012,423 describes how vicinal hydroxy esters may be reacted over group I, II and IIIA basic metal carboxylates, being the preferred catalyst (sodium, potassium, lithium, calcium or barium, etc.), or group I, II and IIIA basic metal simple oxides and complex oxides and organic bases (such as borates, phosphates, oxides and carboxylates, particularly sodium borate, nickel oxide, etc.) to give epoxides. Another method is described in U.S. Pat. No. 4,158,008 whereby propylene glycol monoesters in the presence of a high boiling solvent is reacted over a base to produce propylene oxide. Propylene oxide may also be produced from propylene glycol with the removal of a water molecule over a weakly acidic carrier comprising a basic alkali metal salt of a low molecular weight carboxylic acid as taught by U.S. Pat. No. 4,226,780.
Cycloalkenes are also known to be oxidized. Boron-containing catalysts, in the form of boric acid, boric oxide and boron trialkoxy compounds, are also used in the oxidation of 1,5,9-cyclododecatriene according to Japanese Pat. No. 73-21,936 (Chemical Abstracts 79:104812p). Cyclooctene was oxidized with air at 110.degree. C. for twelve hours in the presence of cobalt naphthenate to give 22% conversion, 56% selectivity to epoxide and 14% selectivity to alcohol plus ketone, according to German Offenlegungsschrift 923,185 (CA 52:4685).
European patent application No. 31,537 teaches epoxide production from olefins, including cycloalkenes, and hydrogen peroxide in an anhydrous solvent containing boron catalysts, such as orthoboric acid. The epoxidation of cyclododecene with performic acid formed in situ is described in European patent application No. 34,206. Methods for the direct oxidation of olefins, including cycloalkenes, in the liquid phase by reacting the olefin with hydrogen peroxide in the presence of a boron-containing catalyst; e.g., boron oxides, boron oxyacids, boron halides and the like, are described in U.S. Pat. Nos. 4,303,586 and 4,303,587. Finally, the liquid phase oxidation of high molecular weight alpha olefins gave poor yields to the epoxides according to C. J. Norton, et al. in Oxidation of Organic Compounds, Vol. I, Advances in Chemistry Series 75, American Chemical Society, Washington, 1968, p. 89, et seq.
U.S. Pat. No. 3,014,928 teaches that the monoepoxide of cyclododecatriene may be formed by the reaction of cyclododecatriene with various per compounds such as monoperacetate, performic acid, perbenzoic acid and peracetic acid in over 90% yields.
Besides the documents discussed in the three preceding paragraphs, the disclosures considered to be most relevant to the invention at issue are U.S. Pat. Nos. 4,012,423; 4,069,381 and 4,220,800, all of which have been discussed.
Despite all of the investigative routes described so far and the ones that have been devised which have not been described, there is still a need for an efficient method for making cycloalkylene oxides from cyclic olefins, which does not involve a highly corrosive or highly expensive catalyst system.